You are right - unfortunately the problem you have experienced with the Skin property is a bug. Sorry for the trouble. The problem was logged as a bug (ID105924).
As a workaround i suggest you to try this:
1. Navigation Control> click Edit
2. Under 'Fine tune the selected type
' section >Click 'Design settings
'> type Skin name ( for example: Vista) in 'Wrapper CSS class (Skin)
' field. The Skin name should be saved.
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